The diagnosis of sigmoid diverticulitis is usually suspected clinically in a patient presenting with acute lower abdominal pain, associated with an inflammatory syndrome with elevated CRP and/or leukocytes count. The preferred imaging modality to establish definitive diagnosis is computerized tomography (CT) scan with triple (oral, intravenous and intra-rectal) administration of contrast. CT scan may also influence management by demonstrating whether sigmoid diverticulitis is simple (phlegmonous, showing an infiltration of pericolic fat and a thickening of intestinal wall) or complicated (abscess, fistula or peritonitis).